1. Field of the Invention
This invention relates to a liquid crystal display LCD system having an anti-static electricity structure and, more particularly, to a liquid crystal display system which can prevent a display error caused by a residual static electricity in the LCD.
2. Description of Conventional Art
In general, a flat display device which can decrease an equipment space compared with a cathode ray tube may be classed in five types, for example, a liquid crystal display, a plasma display panel, a electro luminescence, and a vacuum fluorescent device.
The liquid crystal display displays a picture by using characteristic of twist or dispersion of liquid crystal under the effect of an electric field and selecting a light. The liquid crystal may be classified as a smetic liquid crystal, a nematic liquid crystal, and a cholesteric liquid crystal. The nematic liquid crystal is commonly used for information display and classified again as a twisted nematic TN, a super twisted nematic STN, a double super twisted nematic DSTN and so forth in accordance with a twist angle determined by a rubbing angle of an orientation layer.
As a means for selecting the light, a pair of polarizers crossed to each other are well known.
Referring to FIG. 5, an LCD system comprises an LCD element including a pair of panels 52,53 having common electrodes 50 and segment electrodes 51 respectively; a frit seal for maintaining a predetermined gap between the panels and for sealing up the panels; and a pair of orientation layers 55 covering the common electrodes 50 and the segment electrodes 51 respectively, the common and segment electrodes 50 and 51 being crossed to each other for forming a matrix shape.
An insulting layer is formed each between one orientation layer 55 and the common electrode 50, and the other orientation layer 55 and the segment electrode 51. Further, an anti-electrical charge layer 57 for preventing a static electricity is formed each between one orientation layer 55 and one insulating layer 56, and the other orientation layer 55 and the other insulating layer 56.
The LCD system further comprises a connecter 58 connecting the pair of panels 52,53 to each other, and a circuit board having a driver chip 59.
The LCD system further comprises a back light 61 such as an electroluminescence element mounted between the circuit board 60 and the LCD element. The connecter 58 contacts the lead pattern 62 extending from each of the electrodes 50, 51 and contacts a pattern(not shown) of the circuit board 60 having the same pattern with the lead pattern 62.
A predetermined pattern is put on the orientation layer through a rubbing process, so that the liquid crystal can have a regular characteristic. The insulating layer 56 between the orientation layer 55 and the electrodes 50,51 prevents a short-circuit occurred between the electrodes 50,51.
That is, since a certain liquid crystal of a pixel is twisted in advance by the residual static electricity, the pixel spots, such that the display error occurs. Accordingly the anti-electrical charge layer widely disperses the static electricity to alleviate the spot, thereby decreasing the display error.
However, alleviating the spot by widely dispersing the static electricity to decrease the spot is not effective when the capacity of the static electricity is large.
Further, there is a problem that non-selected pixel is driven by the static electricity, thereby occurring a malfunction.